High-velocity tuyere with variable size cooling medium passage

ABSTRACT

A blast furnace tuyere having a graduated convolute-shaped cooling passage for a cooling medium. The cooling medium travels at a high velocity in a substantially helical movement as it moves along the tuyere.



1. A blast furnace tuyere which will be subjected to a high temperature differential along the length of said tuyere when the tuyere is installed in a blast furnace; said tuyere comprising an outer wall, a nose end, a head end and an inner wall forming a central opening along the longitudinal axis of said tuyere; a cooling medium passage disposed between said central opening and the outer surface of said tuyere, said cooling medium passage comprisiNg: a first convolute-shaped section curved about said longitudinal axis; said convolute-shaped section having an inlet end and an outlet end and two edges; said convolute-shaped secton extending between said head end and said nose end of said tuyere and the cross-sectional area of said convolute section transverse to the direction of flow of a cooling medium, varying in size with the largest crosssectional area of said tuyere being close to said head end of said tuyere and the smallest cross-sectional area being at the nose end of said tuyere; said convolute-shaped section including means for progressively cooling from said head end toward said nose end of said tuyere; one of said edges being spaced from said remaining edge; a second inlet section having one end integral with said inlet end of said convolute-shaped section, and another end terminating at said head end of said tuyere; a third section having one end integral with said outlet end of said convolute-shaped section and extending from said nose end of said tuyere rearwardly toward said head end of said tuyere between said edges of said convolute-shaped section; and a fourth outlet section having one end integral with the remaining end of said third section and another end terminating at said head end of said tuyere; said cooling medium passage comprising said four sections; whereby said cooling medium passage is adapted to receive a cooling medium which moves progressively from said head end toward said nose end and passes through said inlet section, said convolute-shaped section and said third section prior to exiting from said tuyere through said outlet section and the temperature of the tuyere when it is installed in a blast furnace being substantially uniform from said nose end to said head end.
 2. A tuyere in accordance with claim 1 wherein said cross-sectional area of at least said convolute-shaped section decreases progressively said said head end to said nose end of said tuyere.
 3. A tuyere in accordance with claim 2 wherein said cross-sectional area from said head end to said nose end of the portion of the tuyere which is normally located within the working lines of said furnace decreases progressively and inversely proportional to the temperature to which said tuyere will be subjected along said outer wall when said tuyere is installed in a blast furnace.
 4. A tuyere in accordance with claim 3 wherein said cross-sectional areas of at least said convolute-shaped portion increases in a ratio of about 1 to 2 to 1 to 5 from said nose end to that portion of said head end which is normally disposed within said furnace.
 5. A tuyere in accordance with claim 4 wherein said cross-sectional area of said convolute-shaped section at said nose end is a minimum of about 1.20 square inches.
 6. A tuyere in accordance with claim 4 wherein said third section has a rearward, outward taper from said nose end to said head end.
 7. A blast furnace tuyere which will be subjected to a high temperature differential along the length of said tuyere when the tuyere is installed in a blast furnace; said tuyere comprising an outer wall, a nose end, a head end and an inner wall forming a central opening along the longitudinal axis of said tuyere; a cooling medium passage disposed between said central opening and the outer surface of said tuyere, said cooling medium passage comprising: a first convolute-shaped section curved about said longitudinal axis; said convolute-shaped section having an inlet end and an outlet end and two edges; said convolute-shaped section extending between said head end and said nose end of said tuyere and the cross-sectional area of said convolute section transverse to the direction of flow of a cooling medium, varying in size with the largest cross-sectional area of said tuyere being near said head end of said tuyere and the smallest cross-sectional area being at the nose end of sAid tuyere; said cross-sectional area from said head end to said nose end of the portion of the tuyere which is normally located within the working lines of said furnace decreases progressively and inversely proportional to the temperature to which said tuyere will be subjected along said outer wall when said tuyere is installed in a blast furnace; said convolute-shaped section including means for progressively cooling from said head end toward said nose end of said tuyere; one of said edges being spaced from said remaining edge; a second inlet section having one end integral with said inlet end of said convolute-shaped section, and another end terminating at said head end of said tuyere; a third section having one end integral with said outlet end of said convolute-shaped section and extending from said nose end of said tuyere rearwardly toward said head end of said tuyere between said edges of said convolute-shaped section; and, a fourth outlet section having one end integral with the remaining end of said third section and another end terminating at said head end of said tuyere; said cooling medium passage comprising said four sections; whereby said cooling medium passage is adapted to receive a cooling medium which moves progressively from said head end toward said nose end and passes through said inlet section, said convolute-shaped section and said third section prior to exiting from said tuyere through said outlet section and the temperature of the tuyere when it is installed in a blast furnace being substantially uniform from said nose end to said head end. 